Prostate cancer is the second leading cause of cancer related mortality in American men. In 2007, there were 218,890 new cases with 27,000 deaths associated with prostate cancer. It is well known that androgens, such as testosterone and dihydrotestosterone, drive the growth of the prostate as well as prostate cancer at the level of the androgen receptor. The standard of care for advanced hormone sensitive prostate cancer involves surgical or chemical castration with a leutenizing releasing hormone agonist/antagonist to remove the androgens produced in the gonads from circulation. However, approximately 90% of androgens are produced in the testes with the remaining 10% being produced through the action of the adrenal gland. Thus, castration does not alleviate the action of all androgens. Further once a patient progresses to castration resistant prostate cancer, androgens are also produced at the level of the tumor, making treatment with antiandrogens more difficult.
The cytochrome P450 CYP17 is responsible for the biosynthesis of both dihydroepiandrostenedione and androstenedione which are precursors of both androgens and estrogen. Thus the production of all androgens and estrogens produced in the human body is mediated by CYP17. Blocking this enzyme would inhibit the production of gonadal, adrenal and tumoral androgens and could offer a new treatment option for prostate cancer and estrogen receptor-positive breast cancer patients.
Clinical proof-of-concept for CYP17 as a target for prostate cancer has been achieved with the antifungal ketoconazole and the steroidal CYP17 inhibitor abiraterone, which has progressed to Phase III clinical trials for prostate cancer.
There remains a need for compounds that are useful as inhibitors of CYP17 enzymes.
Applicants have found potent compounds that have activity as CYP17 inhibitors. These compounds are provided to be useful as pharmaceuticals with desired stability, bioavailability, therapeutic index, and toxicity values that are important to their drugability.